The Hootie 1.0 Indoor Aquaponic System was able to grow a string bean with only about 100 grams of ornamental goldfish powering the train.

This string bean was just a test to see if we could grow a decent fruiting vegetable with this 29-gallon system. (Fruiting plants like string beans require more nutrients and are generally harder to grow well). Ultimately, this system is best suited to grow seven or eight quick-growing herbs and lettuces at a time because of the small-ish fish tank and wide media growbed.

We were happy to see that – despite its diminutive size – it was a crunchy and tasty little bean!

The Hootie 2.0 Indoor Aquaponic System is equipped with lighting and improved water circulation. Once that system gets to decent fish capacity maybe we’ll try another fruiting veggie… any requests?

Here are some pics from a few months ago of Tavon and Bill performing drum filter maintenance on one of UDC’s aquaponic systems.

A drum filter allows an aquaponic system to divert solid fish waste to a separate tank. In this separate tank the fish waste is able to safely break down and gradually release the bound-up nutrients back into the system.

Fish tank water enters into the center of the drum and must pass through the screen mesh to outside the drum. All solid waste larger than 100 microns is trapped within the drum.

A sensor detects when the drum is to capacity with waste. The drum starts to spin rapidly. Four spray nozzles (which we see Tavon installing below) spray the solid waste off the mesh and flush it to the solids-diversion tank.

Differences of opinion exist within the aquaponics community whether it’s better to break down the solid fish waste aerobically or anaerobically (with or without oxygen). Each process involves a different set of bacteria and different costs and benefits. We shall see how the debate evolves…

Here are two pics from our backyard aquaponic harvest event last month.

Above, Scott is pictured “cleaning” fish we just harvested from his 270 “IBC-tote” fish tank. We ate bullhead catfish, bluegill, and trout.

Below is the finished product, the bluegill were the tastiest! We also ate Baba Ganoush made from eggplants grown in the same aquaponic system; meaning that the eggplants were fertilized from the waste of the very same fish pictured below!

Dan and Dan were recently improving the insulation on one of Cultivate the City‘s rooftop greenhouses ahead of the winter.

This greenhouse hosts a hydroponic system with 25 vertical zipgrow towers; stacked-pot drip-line vertical hydroponic systems; and an aquaponic system we will be overhauling in the months ahead.

Controlled environment agriculture gives us the ability to produce food in the middle of Washington, DC in the middle of winter — as opposed to shipping all of our fresh produce thousands of miles for half the year. And vertical growing gives us the ability to produce large quantities of food relative to square land area.

The problem: our nation’s economic structure. We do not charge the true cost of carbon. Big companies have an implicit subsidy to use as much carbon as they want to get their food here from across the planet and compete against efficient local growers. Sad.

So this year I’m thankful for Dan, Dan, and the rest of the Washington, DC urban agriculture community!

OK, vermicomposting makes sense, but what does a fish harvest have to do with food waste & recovery?

In honor of DC food recovery week we are going to bokashi compost the fish guts. The fish guts and skeletons are extremely rich with nutrients that plants need. There is no reason to send these nutrients hundreds of miles to a landfill to rot. Instead, we can use compost methods to transform and re-use these nutrients right here in our own city. (and on a large scale this will create many JOBS).

Aquaponics can also stem the problem of food waste by providing vegetables to urban and arid areas without crop spoilage during transport.

Our nation wastes thousands of tons of vegetables each year due to spoilage during transport. Contrast this with Scott’s aquaponic system where we’re hosting this event. In the warm months Scott grows an entire salad a day for his entire family that can be harvested the same day they eat it; if we all grew hyper-local like Scott there would be a LOT LESS FOOD WASTE!

Here swim tilapia in the Bertie Backus Urban Food Hub aquaponic system in Northeast Washington, DC. These tilapia are about 6 inches long and reside in one of the six 650-gallon tanks at the Backus system.

The water is very clear due to the use of a 100 micron “drum filter” and 50 micron “tank filter”.

Bertie Backus is one of four Urban Food Hubs constructed and operated by the University of the District of Columbia. UDC also operates aquaponic systems at the Van Ness, P.R. Harris College, and East Capitol Urban Farm food hubs.

The Van Ness aquaponic system was started earliest of the four. We first stocked fish in April, 2017. It’s been successfully growing basil, lettuces, and tomatoes with fish food as the ONLY nutritional input for about 6 months now. After working out initial kinks, water quality parameters are consistently excellent and the fish grow about an inch per month.

Anacostia Aquaponics worked with UDC during the initiation process of these systems from March through September, 2017. It was a great learning experience.

The Hootie 2.0 has been running for a few months and has been growing lots of parsely and watercress (startin’ easy, ya know?) This week we added 4 bigger goldfish so it’s time to graduate to basil and some denser greens, ahhh milestones….

The fish all have names, the parsely is used in group meals, and the residents enjoy feeding the fish. We’re going to work with the chef to figure out how to use the watercress.

Residents and staff asked many great questions about how an aquaponic system functions, and how aquaponics will fit in our evolving food system.